Diversity-combining receiver for FFH/FSK systems over partial-band noise jamming and AWGN channels

• Main Author: Quah, Royston Wee Long.
• Other Authors: Teh Kah Chan
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
• Online Access: http://hdl.handle.net/10356/17294
• Institution: Nanyang Technological University

In this report, bit-error-rate (BER) performance of a fast frequency-hopped frequency-shift-keying (FFH/FSK) system utilizing diversity-combining over a partial-band jamming (PBJ), additive white Gaussian noise (AWGN) and fading channel is studied. BER simulation is conducted for three diversity-combining methods, namely, hard-decision combining, square-law linear combining and product combining. In a PBJ channel, the three diversity-combining methods are able to improve BER performance especially with high diversity level, L. However, this is only true beyond certain signal-to-jammer ratio (SJR) level. In the case of a channel with PBJ and AWGN, with the signal-to-noise ratio (SNR) fixed at 13.35dB, both hard-decision combining and product combining are able to provide improvement to BER for low diversity level and for a small range of SJR levels. However, no improvement is observed for system employing square-law linear combining when diversity level is increased. The three diversity-combining methods are able to improve the BER performance under both Rayleigh and Rician-fading channels with PBJ and AWGN. In addition our study also shows that there exists an optimum L under the conditions specified in this report. Comparing the effects of non-fading, Rician-fading and Rayleigh-fading channels, our studies have also shown that the system performance is the best under a non-fading channel due to the absence of signal attenuation caused by fading. On the other hand, the system performance under a Rician-fading channel is better than that of a Rayleigh-fading channel due to the presence of a dominant line-of-sight component. Among the three diversity-combining methods, the product-combining scheme is able to outperform the hard-decision and square-law linear-combining methods under most conditions specified in this report. Thus, the product-combining scheme is recommended to be used for most practical applications.